Department of Environmental Science and Engineering, Tunghai University, Xitun, Taichung, 40704, Taiwan.
Department of Landscape Architecture, National Chin-Yi University of Technology, Taiping, Taichung, 41170, Taiwan.
Environ Sci Pollut Res Int. 2019 Nov;26(33):34157-34166. doi: 10.1007/s11356-018-3739-7. Epub 2018 Nov 19.
Dispersants including Tween 20, Tween 40, Tween 60, and polyacrylic acid (PAA) were used to modify nanoscale zero-valent iron (nZVI). All dispersants dispersed nZVI effectively. PAA-modified nZVI was more stable than nZVI that was modified with Tween surfactant. Iron nanoparticles that were prepared using 0.5-5.0% (vol%) of PAA remained in suspension for more than 2 h. nZVI that was modified using Tween surfactant remained in suspension for 30-60 min, and there was complete sedimentation of bare iron in 10 min. When 2.0-5.0% (vol%) of Tween surfactant was used, the stability of the nZVI that was modified using Tween 20 was much better than that for nZVI that was modified using Tween 40 or Tween 60. The results for the transportation test show that nZVI that was prepared using 2% (vol%) of Tween 20 exhibited the best mobility in porous media. Approximately 83-90% of TCE was degraded by bare, PAA-modified, and Tween 20-modified nZVI, and about 63-67% of TCE was removed by nZVI that was modified using Tween 40 and Tween 60 during 20 days of reaction. The production of cis-dichloroethene (DCE) and 1,1-DCE demonstrates that TCE is removed via reductive dechlorination. The results of this study show that PAA- and Tween 20-modified nZVI are more practical for in situ remediation because they exhibit good mobility and degrade TCE effectively.
分散剂包括吐温 20、吐温 40、吐温 60 和聚丙烯酸（PAA）被用于修饰纳米零价铁（nZVI）。所有的分散剂都有效地分散了 nZVI。PAA 修饰的 nZVI 比用吐温表面活性剂修饰的 nZVI 更稳定。用 0.5-5.0%（体积%）的 PAA 制备的铁纳米颗粒在悬浮液中保持超过 2 小时。用吐温表面活性剂修饰的 nZVI 在悬浮液中保持 30-60 分钟，10 分钟内裸铁完全沉淀。当使用 2.0-5.0%（体积%）的吐温表面活性剂时，用吐温 20 修饰的 nZVI 的稳定性远优于用吐温 40 或吐温 60 修饰的 nZVI。传输测试的结果表明，用 2%（体积%）的吐温 20 制备的 nZVI 在多孔介质中表现出最好的迁移能力。大约 83-90%的三氯乙烯（TCE）被裸铁、PAA 修饰的和吐温 20 修饰的 nZVI 降解，大约 63-67%的 TCE 在 20 天的反应中被用吐温 40 和吐温 60 修饰的 nZVI 去除。顺式-二氯乙烯（DCE）和 1,1-二氯乙烯的生成表明 TCE 通过还原脱氯去除。本研究的结果表明，PAA 和吐温 20 修饰的 nZVI 更适合原位修复，因为它们表现出良好的迁移能力和有效地降解 TCE。
